Large-Vessel Vasculitis

GCA almost never occurs in a patient younger than 50 years of age. One of every 10 patients with GCA has negative temporal artery biopsy specimens, even if bilateral biopsies are performed. One of every 10 patients with GCA has an ESR <50 mm/hour. By itself, a highly elevated ESR (e.g., >100 mm/hour) is not a powerful predictor of GCA. Jaw claudication and diploplia are extremely useful in predicting which patients will have a positive temporal artery specimen. Classic GCA symptoms, such as headache, PMR, and visual symptoms other than diplopia, are not. Temporal artery biopsies may confirm the diagnosis of GCA even weeks after therapy with glucocorticoids has begun. The presence of fibrinoid necrosis on a temporal artery biopsy should prompt the search for forms of systemic vasculitis other than GCA, such as PAN or the ANCA-associated vasculitides. Ultrasound of the temporal arteries adds little to a thorough physical examination when evaluating a patient for GCA. MRI/A is useful in identifying the vascular abnormalities associated with TA, but the presence of vessel edema alone is not an accurate gauge of disease activity. PET and EBCT should still be considered experimental modalities in the evaluation of the large-vessel vasculitides. GCA patients with highly elevated ESRs may be less likely to experience vision loss. The specific reasons for this observation, if true, remain under investigation. Patients with hyperacute vision loss from GCA (e.g., within 24-48 hours) should be treated with high-dose, intravenous glucocorticoids. GCA patients without contraindication to aspirin therapy may benefit from adjunctive therapy with dosages as high as 325 mg 3 times per day.